Mold and method of manufacturing the same



Jan. 6, 1931; M. E. GATES 1,788,101

MOLD ND METHOD OF MANUFACTURING THE SAME Filed July 19, 1928 du wa 111,75,

Patented Jan. 6, 1931 ,fil-UNITED STATES Ol-*Fleag yMAJOR, n. GATES, or CRYSTAL LAKE, 1"II.1NorsffI l l 'MOLD AND METHOD 0F MANFACTURNG THE y @Application meaamy 19,

` My vinvention relates more'pa'rticularly to the manufacture of molds of comparatively fragile materiah'as for example plaster of Paris, formed about patterns of such form 1l that'the pattern and the mold, the latter as aunit,can`1iot beseparated, but requires that` the-mold 'be displaced, from the pattern in sections, my invention relating particularly, though not exclusively, to the molding `of 10 clay`blocks,ror` the like, as for example terra cottablocks. v

` In connection with the manufacture of building blocks, as for example of terra cotta,- thecommon practice, is to make the kmold,

-- usually'of plaster ofv Paris, in separate, sep` arable, sections to permit of the separation of the mold'fromthe pattern, the sections being thereafter reassembled to form tliemold in which-the blocks lare tobe molded, this practice presentin-gobj'ections, one of which is that the production of blocks in this way is' relatively expensive and the operation is arcomparatively slow onen l My primary object is' to greatlyireduce the y; .2.5 cost 'of manufacture of such articles and nto reduce the timenecessary for -producingrany given number of the articles.

1 Generally stated my invention consists in molding about the pattern ya Isettable material which is comparatively fragile when set,

V thereof, thatthe molded mass'upon the application 'of fracturing stresses thereto, will fracture along sucha line, or lines, that the mold may be separated freely in sections from the pattern.

Referring to the accompanying drawings Figures land .2 relate towthe production of a mold in .which substantially rectangular objects,isuch as terra cotta building blocks,

' are molded; and l.

Figure 3, to a structure in which cylindrical blocks, as for example, blocks for the forming ofk a column,are to be molded, Fig. 1 kbeing a perspective view of a pattern of a building block shown as equipped with means 192s. serial no. 293,904.;l

whereby the mold structure to be produced will'be fractured, upon applying fracturing stresses thereto, along the desired lines. Figure 2 is a view in'sectional elevation of the moldfstructure as cast about'the pattern; 55l

and Figure 3, a plan sectional viewf'of the moldstructure' 'for the cylindrical blocks, as cast about the pattern therefor.

' Referringlirst to the construction of molds for buildnig blocks in accordance withl Figs. 6G;

four marginal edges of its face portion 5 70' withstrips 7 yofany' suitablematerial, as for examplemetal, secured tothe pattern in any v desirable way, as for'example by fitting them into grooves in the pattern at the portions referred to, these grooves along the ends of the face 5 ofthe pattern being represented at 8, thet strips;y 7v being ,disposedy kpreferably atsubstantially 45 to the adjacent sides of the pattern, as shown.

. Inf the formin ofthe mold the vpattern 4 80 is laidupona vta le 9 with its face yportion 5 uppermostand a rectangular vmold frame 10 placed upon the tableto surround the ypattern but inspaced relationship to all our side walls of the latter to provide a rectangu- 8 5-k larshaped mold-space 11 between the pattern 4 andthe frame 10, which latter extends up! wardly a short distance beyond the face 5 of the pattern.' i The .material,` such as Huid plaster of Paris, and from which the mold, 9G represented at 12, is to be formed, is then any suitabletool, as for example, a chisel, apico plies force to the mold 12, thus formed, to

subject it to fracturing stresses adjacent the mold is formed to be weakened at these strips vand thus the mold fractures along the corners of the pattern ,fi at whichcfthesestrips are located :thereby causing thermold 121:0 be re.-

duced fromanfintegral structure ,into live separate pieces permitting of the free sep-` aration thereof from the 'pattern and the reeseembling of thesepeeeste. preclueee meld in which the blocks to be molded and likeV Y ythe,material of which the mold 19 is to be the pattern may be formed. Y, -V

If desired the outer Asurfaces of Ythe mold 12,::et which it isVv desired the freeturing stresses be applied, Vmay 'bei indented `or grooved in the operation ef .forming the Inoldythese indentations or grooves'if desired, extending 'the full lengthA of agllbofthe strips 7. Y ,i Y n In Fig. 2 l have lshownmeanszfor forming such indentations vor grooves, represented at 13, along the `strips 7 latthe under edges of Vto the face portion 5 and'which is typical of the means whichY may be provided adjacent the others ofthe strips-7.

vThe means'j ust referred to are in `the form of strips 14 shown as secured in slots 15 in the lwall portions of the mold frame :10 and projecting inwardly-therefrom into'the inold cavity 11 providedV by this frame, in a substantially horizontal v direction adjacent the upper edges -of the st-rips :7,pit being understood that the .strips `14: for the vertical -strips 7 would be vertically positioned in the frame l0 and extend substantially vertically in the same relativepositions to these strips as tle relationship-shown in Fig. 2' between the strips 7 and k116i.

` the grooves 13, 4formed "by the strips*14,-tlie mold 12 will crack in a direction toward, and to, the outer edges of Vthe `strips 7 and. the

cracks will then folloW inwardly along :these strips and. through the inner surface of the mold. r While the strips 7 are shown in such a position that they' extend through the'corners of the mold cavity, it will be understood-that if desired these strips may be set back 'from the corners in which case the inner surface of the mold will becontinuous at the corners of the mold cavity, as distinguished from containing the narrow slits formed by providing' the strips 7 on the pattern. In such modi'- fied structure, the strips 7 would be Vlocated sutliciently close to the cornersof the mold cavity that the material of the mold would crack 'at lines substantially in registration with the apices of the corners ofthe mold cavity.- v-

Referring to Fig. 3, which represents my invention applied to the manufacture ofcy- L'I`l1e-mold"19 may-'beV formed as described `et the meld of Fig--2,tl1e pattern 16 and the mold ring `17 "being lplaced upon a table and formed, poured into the mold space 18, the ,moldy 19 produced thereby eenteining the mold cavity 20. Y I A The mold 19 is formed with, weakening lines along which the mold SPISQ eeetions upon applying Af,filete-riug Ythereto, the ineens .shown in this arrangement for this purpose being in the'- fo rnr `of strips 2.1 like thel Stripe 7 radiating outwardly from the periphery of the pattern 1.6 to become bedded ais-their outer edge portions-.11,1 .theiilr ner surface of the mold cavity 20, For sepa.- rating the mold 1 9 from the pattern y16 the operator applies freeturiilg stresses tothe' mold 19 from the exterior ef the letter ediaeent the Stripe' 2li, as by means of Le eihieel.,` the 1110,11'19 freeturing toward, and te, the strips 21,-the mold seetiens thus produced being separated from eaeh' ether ret-the strips 2 1- Upon reeseemblng the meld ,Sect-iene' an article of the form ofthe pattern 16 may be molded therein. Y i

The strips 21 in vthe case of this con st-rue` tion, as in the caseof thatjshovvnI tlieprer ceding igures, need not penetrate lthe inner surface of the mold cavity '20 but may be so positioned as vto be confined between the'nner andouter walls of the mold 19 in which CaSe they Vwould function as explained of the modification of the positioning ofthe :strips 7 ofFig. 2, Yto deine'the lines along which the mold would crack at its inner surface.

Of course, it will be lunderstood :that if desired grooves 'may be Yformed i-n the .outer surface of the mold 19 generally as explained of the construction shown in Fig. 2 in which case, however, the groove-forming strips would preferably be 'aligned' radially'wiith the strips 21 but spaced radially from I,the latter.

While I have described my invention`V as employing the use of elements at which 4the mold is relatively weakened and determining the lines along which :themold 'Willfractura when fracturing stress is applied thereto, it will be understood the invention is not limited thereto as the weakening of the moldto determine the lines along which it separates, into sections, at it-svinner surface may be effectedV in other ways, within the spiritof myL invention. v

What I claim as new, and desire to secure by Letters Patent, ist, .l

1. In the art of molding, the improvement which consists in casting mold-forming, settable, relatively fragile, material abolita lpatternto form amold from which the patv pattern to form a mold from which the pattern cannot be removed without breaking the mold, producing in they casting of the mold a weakening ofthe portion of the mold adjacent to which it is desired the mold fracture in separating it fromgthe pattern and subjecting the mold to fracturing stresses adjaj cent the said weakened portion ofthe mold structure.

3. In the art ofmolding, the improvement which consists in casting mold-forming settable, relatively fragile, material, about. a pattern to form a mold from which the pattern cannot be removed without breaking the mold, producing a weakening of the mold structure at the portions thereof adjacent to which it is desired the mold structure be frac'- tured and subjecting the mold to fracturing stresses adjacent said portions of the mold` structure.

4. In the art of molding, the improvementwhich consists in casting mold-forming, settable, relatively fragile, material about a pattern to form a mold from which the pattern cannot be removed without breaking the mold, producing a weakening of the portion which consists .in casting mold-forming settabIe, relatively fragile, material, about a pat-tern to form a mold from which the pattern cannot be removed without breaking the mold, producing a weakening' of the mold structure at the portions thereof adjacent to which it is desired the mold structure be fractured, subjecting the mold to fracturing stresses adjacent said portions vof the mold structure to breakthe mold structure into sections, and thereafter reassembling the sections into mold-forming condition.

MAJOR E. GATES.V

of the mold adjacent to which it is desired i the mold fracture in separating it from the pattern, subjecting the mold to fracturing stresses adjacent thel said weakened portion of the mold structure to break the mold structure into sections, and thereafter reassembling the sections into mold-forming condition. 2

5. In the art of molding, the improvement which consists in casting moldforming settable, relatively fragile, material about a pattern to form a mold from which the pattern cannot be removed without breaking the mold, producing in the casting ofthe mold a weakening of the portion of the mold adj acent to which it is desired the mold fracture in separating it from the pattern, subjecting the mold to fracturingy stresses adjacent the said weakened portion Vof the mold structure to break the mold structure into sectionsand thereafter reassembling the sections into mold-forming condition.

6. In the art of molding, the improvement 

